This invention relates in general to sewing machines and in particular to a device for stopping a sewing, embroidering or tufting machine upon a thread breakage.
U.S. Pat. No. 4,429,651 discloses such a stopping device in which the piezoelectric element, serving as the thread feeler responsive to the thread deflection, is mounted by means of a soft rubber and a holder at a location which is particularly suitable for the detection. The thread feeler is near the needle hole at the underside of the needle plate and in the space through which, in machines equipped with a thread cutting mechanism, the thread catcher must move to separate the threads from each other and engage them, so that it necessarily would collide with the thread feeler. The mounting of the thread feeler in the close vicinity of the needle hole would prevent a feed catcher from moving into this space.
Since a thread cutting mechanism considerably improves the efficiency, and monitoring of thread breakages with sensitive stopping devices for quickly disconnecting the sewing machine and eliminates time consuming and costly refinishing operations, it is desirable to equip the machine with both a thread cutting mechanism and a reliably and quickly responding stopping device.